#!/usr/bin/perl

use warnings;
use strict;

my $ZERO = -459.69;

print "Please enter the start F degree: ";
my $start_degree = <STDIN>;
print "Please enter the end F degree: ";
my $end_degree = <STDIN>;
print "Please enter the offset degree: ";
my $offset = <STDIN>;

if ($start_degree < $ZERO) {
    print STDERR "Start degree is less than absolote zero.\n";
}

if ($start_degree > $end_degree) {
    print STDERR "Start degree is larger than end degree.\n";
}

